A more sustainable construction industry is unimaginable without a drastic increase in conversion projects. The preservation, transformation, and repurposing of existing buildings, and the reuse and recycling of used materials, components, and infrastructures is not only one of architecture’s oldest tasks, but is also one of its most important and topical missions at the start of the 21st century.
Conversion is associated with the rediscovery of an ancient cultural technique. It wasn’t until the 20th century that industrialized construction began to increasingly favor the practice of demolition and new construction. Repairing, maintaining, and constantly updating existing structures was suddenly perceived as inconvenient, expensive, and complicated. Why patch something up when you can buy something new? Today this throwaway mentality poses a serious dilemma. According to a report by the United Nations Environmental Program, the global construction industry was responsible for 9.95 gigatons of CO² emissions in 2020. That’s easily 38 percent of all man-made greenhouse gas emissions and puts emissions by the construction industry at an all-time high — diverging from the climate goals that were defined in Paris to keep our planet from overheating and becoming uninhabitable. Each year, 75 billion tons of concrete are currently being installed worldwide. Just producing the necessary cement results in 3 billion tons of CO² emissions, which is about three times as much as emissions from global air traffic. If cement were a country, it would be the world’s thirdlargest carbon emitter after China and the U.S. Aggregates like sand and gravel have also become valuable raw materials because of their growing scarcity. And if the world population continues to climb at the predicted rate until 2050, the long-term goal of a climate-neutral construction industry will become increasingly unrealistic.
If we take seriously the challenges of a “green transformation of construction” to the point of a fully sustainable construction industry, then an emphasis on the conversion of existing buildings becomes one of our most valuable tools. Those who convert, repurpose, extend, and update save resources, avoid waste, and conserve the gray energy stored in existing buildings. We need a refurbished conversion culture that sees existing structures as objects of value and repositories of raw materials. And we need architecture that recognizes the potential of existing buildings and knows how to exploit it. It isn’t about retaining buildings at any price. Nor is it about making as few changes as possible for sentimental reasons. It’s a matter of constantly refining these buildings, improving them with the latest technologies, newest materials, and our current knowledge. It’s about a culture of continuous building updates. It’s the only way for our buildings to meet society’s constantly evolving requirements. Outside the museumization of specific monuments chosen for permanent preservation on the basis of their unique value, we need to adopt a mentality that understands the preservation of the ordinary structures around us as something dynamic and precious. Our everyday architecture can only endure if we continually modify it.
The age of conversion, of Umbau, has long since begun. Architectural culture is already undergoing a deep-seated transformation. We no longer look at conversion as an economical stopgap solution simply because there’s not enough money for a new building. We’ve long come to appreciate the special qualities of preservation and of the multilayered transformations that a creative conversion culture is able to produce. Brilliant icons of this new conversion architecture were built at the start of the 21st century, cathedrals to the age of conversion, ranging from Herzog & de Meuron’s Tate Modern in London and David Chipperfield’s Neues Museum in Berlin to Lacaton & Vassal’s Palais de Tokyo in Paris. How bland and one-dimensional the Guggenheim Museum in Bilbao now seems by comparison, although just 25 years ago it was the building that most represented the future of construction. Today it seems like a relic from the past, a final, over-the-top example of the architectural extravagance of the 20th century with its perpetual, breathless, superficially glittering new inventions. Advocating for cautious and ongoing reconstruction doesn’t mean opposing all new construction. Demolitions and new buildings will also exist in the future. But in the 21st century, this practice should be the exception and no longer the rule. Nor would a radically strengthened conversion culture be a “pure doctrine” of renunciation. On the contrary, experts are saying that the adaptations necessary in all the disciplines involved in construction will unleash such a powerful wave of innovation that we could enter a new phase of the industrial revolution. More conversion doesn’t mean less architecture. A good conversion requires more creativity than a comparatively less complex new building. It requires more courage, more imagination, more finesse, and generates more complex buildings — on the whole, that’s definitely more architecture. There’s no doubt about it. In addition to the structural innovations that we’re already experiencing today in areas like timber construction, one of the world’s most exciting future laboratories of architecture in the 21st century will be conversion.
The Umbau exhibition offers a look at actual practice. In addition to their better-known, new construction projects, the architects at Gerkan, Marg and Partners (gmp) have also been continually engaged in conversions of all magnitudes since the 1970s. Over a period of forty years, they’ve implemented more than sixty conversion projects, seven of which are featured in this exhibition. The projects selected exemplify the architectural practice of conversion at gmp. Each time, a precise survey of the existing structure resulted in a highly individualized approach for producing custom-made architecture. When placed side by side, the seven projects also demonstrate the underlying, transferrable methodology. Basically, it always comes back to a reactivation of the existing structure, to the vibrancy and variety of its uses. Regardless of whether a building was active and frequently visited, like the Olympic Stadium or Staatsbibliothek in Berlin, or was abandoned and deserted, like the Hyparschale in Magdeburg or the stainless-steel factory in Shanghai, they had all “fallen behind the times” in various ways — which is basically what made their conversion necessary in the first place. They all had to be reactivated; they all needed more uses, more functions, more convenience, and more vitality; in other words, more everyday practical value for today’s society. Ultimately, conversion is also about restoring a building’s appeal so that it can once again attract people and make a contribution to the city and society. Then it returns to being — or continues to be — good architecture.
Florian Heilmeyer (b. 1974) is an author, editor, curator, and designer in the domain of architecture and the city. He lives and works on the go, mainly in Berlin since 1978. He was already writing about architecture during his architectural studies in Berlin and Rotterdam. Since 2004, he has dedicated himself exclusively to architectural outreach through exhibitions, books, texts, city tours, presentations, and panel discussions. Twice he’s been a direct participant in German contributions to the Architecture Biennale in Venice: Updating Germany (Friedrich von Borries and Matthias Böttger) in 2008 and Reduce ReuseRecycle (Muck Petzet, Konstantin Grcic, and Erica Overmeer) in 2012.